Vulnerability Database

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Total vulnerabilities in the database

CVE-2026-31824 — sylius / sylius

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Sylius is an Open Source eCommerce Framework on Symfony. A Time-of-Check To Time-of-Use (TOCTOU) race condition was discovered in the promotion usage limit enforcement. The same class of vulnerability affects the promotion usage limit (the global used counter on Promotion entities), coupon usage limit (the global used counter on PromotionCoupon entities), and coupon per-customer usage limit (the per-customer redemption count on PromotionCoupon entities). In all three cases, the eligibility check reads the used counter (or order count) from an in-memory Doctrine entity during validation, while the actual usage increment in OrderPromotionsUsageModifier happens later during order completion — with no database-level locking or atomic operations between the two phases. Because Doctrine flushes an absolute value (SET used = 1) rather than an atomic increment (SET used = used + 1), and because the affected entities lack optimistic locking, concurrent requests all read the same stale usage counts and pass the eligibility checks simultaneously. An attacker can exploit this by preparing multiple carts with the same limited-use promotion or coupon and firing simultaneous PATCH /api/v2/shop/orders/{token}/complete requests. All requests pass the usage limit checks and complete successfully, allowing a single-use promotion or coupon to be redeemed an arbitrary number of times. The per-customer limit can be bypassed in the same way by a single customer completing multiple orders concurrently. No authentication is required to exploit this vulnerability. This may lead to direct financial loss through unlimited redemption of limited-use promotions and discount coupons. The issue is fixed in versions: 1.9.12, 1.10.16, 1.11.17, 1.12.23, 1.13.15, 1.14.18, 2.0.16, 2.1.12, 2.2.3 and above.

CVSS v3:

  • Severity: High
  • Score: 8.2
  • AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Software Affected versions
Composer icon sylius / sylius < 1.9.12
Composer icon sylius / sylius >= 1.10.0, < 1.10.16
Composer icon sylius / sylius >= 1.11.0, < 1.11.17
Composer icon sylius / sylius >= 1.12.0, < 1.12.23
Composer icon sylius / sylius >= 1.13.0, < 1.13.15
Composer icon sylius / sylius >= 1.14.0, < 1.14.18
Composer icon sylius / sylius >= 2.0.0, < 2.0.16
Composer icon sylius / sylius >= 2.1.0, < 2.1.12
Composer icon sylius / sylius >= 2.2.0, < 2.2.3

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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